U.S. patent application number 12/667495 was filed with the patent office on 2010-08-05 for rotor head of remotely-controlled helicopter and remotely-controlled helicopter.
This patent application is currently assigned to HIROBO CO., LTD.. Invention is credited to Kimio Nakamura, Takakazu Uebori.
Application Number | 20100196161 12/667495 |
Document ID | / |
Family ID | 40225775 |
Filed Date | 2010-08-05 |
United States Patent
Application |
20100196161 |
Kind Code |
A1 |
Uebori; Takakazu ; et
al. |
August 5, 2010 |
ROTOR HEAD OF REMOTELY-CONTROLLED HELICOPTER AND
REMOTELY-CONTROLLED HELICOPTER
Abstract
When an R/C helicopter of a single rotor type is configured to
have a small size and light weight to be used indoors, a flying
operation thereof can be stabilized and operability can be
improved. A center hub that supports a rotor head to a mainmast is
divided into an upper center hub and a lower center hub, and the
upper and the lower center hubs are fixed around the shaft of the
mainmast with a predetermined angle. A phase angle of a main rotor
as an output with respect to an operation input from a swash plate
becomes an acute angle, and the main rotor and a stabilizer are
mounted to rotate with a phase difference of the acute angle.
Inventors: |
Uebori; Takakazu;
(Fuchu-shi, JP) ; Nakamura; Kimio; (Kawasaki-shi,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
HIROBO CO., LTD.
Fuchu-shi, Hiroshima
JP
|
Family ID: |
40225775 |
Appl. No.: |
12/667495 |
Filed: |
July 2, 2007 |
PCT Filed: |
July 2, 2007 |
PCT NO: |
PCT/JP2007/063232 |
371 Date: |
December 31, 2009 |
Current U.S.
Class: |
416/134A |
Current CPC
Class: |
A63H 27/12 20130101 |
Class at
Publication: |
416/134.A |
International
Class: |
B63H 1/06 20060101
B63H001/06 |
Claims
1-3. (canceled)
4. A rotor head of a remotely controlled helicopter of a single
rotor type, which is configured such that a stabilizer or a main
rotor is connected to a swash plate through a link mechanism, pitch
angles of the stabilizer and the main rotor are controlled by
inclining the swash plate, and the remotely controlled helicopter
flies, wherein the rotor head is configured such that a gyro
pre-session of the main rotor as an output with respect to an
operation input from the swash plate by a decrease in the weight of
the main rotor appears in a range lower than 90 degrees, and the
main rotor and the stabilizer are mounted to rotate with a phase
difference of an acute angle.
5. The rotor head of a remotely controlled helicopter of a single
rotor type according to claim 4, wherein the rotor head has the
configuration of a Bell-Hiller type where the stabilizer and the
main rotor are connected to the swash plate through the link
mechanism.
6. The rotor head of a remotely controlled helicopter of a single
rotor type according to claim 4, wherein configuration of a swash
linkage that connects the rotor head and the swash plate is a Bell
type or a Hiller type.
7. A remotely controlled helicopter comprising the rotor head
according to claim 5.
8. A remotely controlled helicopter comprising the rotor head
according to claim 4.
9. A remotely controlled helicopter comprising the rotor head
according to claim 6.
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotor head of a remotely
controlled helicopter (hereinafter, referred to as R/C helicopter)
that flies by remote control based on wired communication or radio
control based on wireless communication, and more particularly, to
a mechanism of a rotor head that is suitable for an R/C helicopter
of a single rotor type that is configured to incline a rotation
surface of a main rotor by a Bell type, a Hiller type, or
Bell-Hiller type.
BACKGROUND ART OF THE INVENTION
[0002] An R/C helicopter rotates a main rotor blade that is applied
with an angle of attack and generates lifting force, changes the
angle of attack of the main rotor blade through a link mechanism
from a swash plate mounted to a base portion of a mainmast, and
inclines a rotation surface of a rotor using the change in the
lifting force to generate thrust force in an inclined direction,
thereby flying.
[0003] As a method that controls a pitch angle of the main rotor
blade, a Bell type that directly inclines the main rotor blade
through the link mechanism from the swash plate and a Hiller type
that inclines a stabilizer blade through the link mechanism from
the swash plate, transmits a balance change in the lifting force
generated by inclining the stabilizer blade to the main rotor
blade, and changes the pitch angle are used. In the R/C helicopter,
since excellent steering responsiveness is obtained by control of a
Bell-Hiller type corresponding to a combination of the Bell type
and the Hiller type, the Bell-Hiller type is widely used in general
(for example, refer to Patent Documents 1 and 2).
[0004] The reason why the rotation surface of the main rotor is
controlled to be inclined in the same direction as the swash plate
by the inclining operation of the swash plate is as follows. If
force is applied to a rotating object, a gyro pre-session where an
effect of the force appears in a progress direction of a rotation
of 90 degrees acts. In order to cause the main rotor and the
stabilizer to control external stress applied to an airframe by an
effect of the gyro pre-session and stabilize the flying operation,
in the R/C helicopter of the Bell-Hiller type, a phase difference
of an output with respect to an operation input is set as 90
degrees, and the stabilizer and the main rotor are disposed in
directions orthogonal to each other.
[0005] [Patent Document 1] Japanese Utility Model Application No.
H6-7751
[0006] [Patent Document 2] Japanese Patent Application Laid-Open
No. 2003-103066
DISCLOSURE OF THE INVENTION
Problem to be Resolved by the Invention
[0007] In recent years, in indoor living, in order to enjoy a
flying operation of the R/C helicopter, an indoor helicopter that
has the airframe weight of 400 g or less has been demanded.
[0008] In the R/C helicopter of the Bell-Hiller control type that
has been commercially marketed, there various types of R/C
helicopters exist, such as one which the total length of the
airframe is about 1 m and the weight is about 3 kg and one which
the total length over 2 m. However all of them are developed for
the purpose of enjoying outdoor flying control. For this reason, it
is increasingly required to develop indoor helicopters.
[0009] In order to adjust to the above requirement, if the
conventionally used R/C helicopter of the Bell-Hill type is scaled
down and the airframe thereof is small-sized and light-weighted, a
helicopter that enables an indoor flying operation can be
configured.
[0010] However, when the airframe is small-sized and light-weighted
to be used for an indoor helicopter, the flying operation is
unstable and the control operation becomes extremely difficult.
Even in a simple operation from leaving the ground to hovering, a
sophisticated operation technique of a level higher than a level of
when a large outdoor machine is operated is needed. If an operation
stick of a transmitter (propo) is operated to fly the airframe
backward and forward or leftward and rightward, the flying posture
is collapsed or the airframe shakes. At this time, if a user steers
the airframe to stabilize the flying operation, the airframe shows
the behavior of the airframe being greatly rocked in an operation
direction, and the user cannot cause the airframe to smoothly fly
in a desired direction.
[0011] With respect to the behavior of the airframe, stability of
the airframe can be improved by changing the shape of the blade of
the main rotor or the blade of the stabilizer or precisely
adjusting a Bell-Hiller ratio of a rotor head. However, even though
the above adjustment is performed, when the operation of moving the
airframe in a desired direction, that is, inclining the swash plate
and changing the rotation surface of the main rotor is performed,
the user cannot accurately and stably fly the airframe in the
desired direction, the collapse of the flying posture is inevitably
generated, and operability of the conventional outdoor R/C
helicopter is not obtained.
[0012] The prevent invention has been made in view of the
above-described problems in the related art, and it is an object of
the present invention to stabilize the flying operation of an R/C
helicopter and improve operability thereof, when the R/C helicopter
is configured to have a small size.
Means for Solving the Problem
[0013] In order to solve the above-described object, a rotor head
according to the present invention is a rotor head of an R/C
helicopter of a single rotor type and is characterized by having
configuration which when a phase angle of a main rotor as an output
with respect to an operation input from a swash plate becomes an
acute angle, the main rotor and a stabilizer are mounted to rotate
with a phase difference of the acute angle.
[0014] In the above configuration, preferably, a center hub that
supports the rotor head to a mainmast is divided into an upper
center hub and a lower center hub, and the upper and the lower
center hubs are fixed around the shaft of the mainmast with a
predetermined angle, that is a predetermined position, and the main
rotor and the stabilizer are mounted to the upper and the lower
center hubs, respectively.
[0015] Further, an R/C helicopter according to the present
invention comprises the rotor head of the above configuration.
[0016] Not only control operation of an indoor R/C helicopter that
is configured to be able to fly indoors is known to be very
difficult, but also that of an R/C helicopter of a Bell-Hiller type
is very difficult. One of reasons why the control operation is
difficult is that the indoor helicopter is light-weighted and the
flying operation thereof is affected by an indoor moderate
wind.
[0017] In the related art, in general, the flying operation of the
indoor helicopter becomes unstable due to the light weight of the
airframe. That is, the flying operation cannot be prevented from
becoming unstable, as long as the weight of the indoor airframe
cannot be increased. Therefore, it is thought that in order to
stabilize the flying operation, in addition to a Bell-Hiller ratio
of the airframe, adjustment places and a characteristic of a
control signal output from a transmitter need to be precisely
adjusted, and operation skills of an operator of the transmitter
need to be raised.
[0018] As a result of various studies on a method of stabilizing
the flying operation of the R/C helicopter configured to have a
small size to be used indoors, the inventors of the present
invention have found that a gyro pre-session effect appears at a
position different from a common position, when the main rotor
blades are formed of a light-weighted material and the main rotor
is configured to have light weight, and have reached the invention
of the R/C helicopter having the above configuration.
[0019] That is, as in the outdoor R/C helicopter, when the main
rotor blades are made of wood or FRP and have high rigidity and
heavy weight, the gyro pre-session appears after being delayed by
90 degrees with respect to an input. Using these characteristic, a
steering operation is input at an advanced place by 90 degrees with
respect to a moving direction of the main rotor, that is, the swash
plate is inclined at an advanced position by 90 degrees, and the
pitch angle of the main rotor is changed.
[0020] Meanwhile, it is revealed that the gyro pre-session appears
in a range lower than 90 degrees with respect to the input, as a
result of confirmations of a position where the gyro pre-session
appears by trial and error, when the light-weighted main rotor
blades made of a plastic material such as expanded polystyrene is
mounted to the R/C helicopter configured to have a small size to be
used indoors.
[0021] On the basis of the knowledge, in the rotor head of the R/C
helicopter of the Bell-Hiller type that is configured to have the
small size to be used indoors, the main rotor is adjusted such that
the phase angle of the main rotor as the output with respect to the
operation input becomes an acute angle lower than 90 degrees, that
is, the main rotor is disposed around the mainmast such that the
mounting position of the main rotor from the mainmast is advanced
by the appropriate angle, and the main rotor and the stabilizer are
configured to rotate with the phase difference of the acute
angle.
[0022] It can be confirmed that operability is greatly improved
that when the R/C helicopter comprising the rotor head is made to
fly, the airframe does not shake and maintains the stable flying
posture and even when the flying direction is changed, the flying
posture is not collapsed, the behavior of the airframe is
stabilized, and the smooth flying in a desired direction is
enabled.
[0023] It is thought that in the R/C helicopter of the Bell-Hiller
control type, due to a change of the rotation surface of the main
rotor which is made by the cyclic pitch control and the stabilizer
which seesaws above the mainmast as well as the position of the
main rotor is advanced by an appropriate angle and the main rotor
is disposed such that the phase difference with the stabilizer
becomes the acute angle, a direction of the force applied to the
airframe by the gyro pre-session in the rotation surface of the
main rotor and a control direction of the airframe are matched with
each other, and the arrangement of the main rotor is
appropriate.
[0024] According to the present invention, in the rotor head of the
R/C helicopter that is configured to have the small size and the
light weight, the phase angle of the main rotor with respect to the
operation input from the swash plate is adjusted in a range of the
acute angle, not 90 degrees, and the phase angle of the rotation of
the main rotor and the stabilizer is also set to the acute angle.
As a result, the flying operation of the R/C helicopter can be
stabilized and the operability can be greatly improved.
[0025] Accordingly, the problem according to the related art in
that the control operation of the indoor helicopter is difficult
can be resolved. Even when the setting place of the airframe or the
transmitter is not precisely adjusted and the operator lacks
his/her operation skills, the operator can enjoy the control of the
R/C helicopter indoors without difficulty.
[0026] According to the experiments of the inventors of the present
invention, it is confirmed that the range of the phase difference
of the rotation of the main rotor and the stabilizer is different
depending on the configuration of the R/C helicopter, such as the
weight or the size of the main rotor blade and the total weight of
the airframe. For this reason, the optimal phase difference (angle)
to achieve the stable flying needs to be appropriately adjusted and
set according to the configuration of the R/C helicopter. Even in
any case, when the main rotor blade is light-weighted, the gyro
pre-session appears after being delayed by the angle lower than 90
degrees with respect to the input. In order to stabilize the flying
operation, the phase difference of the rotation of the main rotor
and the stabilizer needs to be maintained at the acute angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of a mechanism for constituting
a rotor head and a swash linkage of an R/C helicopter according to
one embodiment of the present invention.
[0028] FIG. 2 is a development perspective view of constituent
members of the mechanism of FIG. 1.
[0029] FIG. 3 is a development enlarged view of constituent members
of a peripheral section of a swash plate in FIG. 2.
[0030] FIG. 4 is a development enlarged view of constituent members
of a peripheral section of a main rotor in FIG. 2.
[0031] FIGS. 5A and 5B are enlarged longitudinal cross-sectional
views of essential parts of a connecting portion of a main rotor
and a mainmast.
[0032] FIG. 6 is a development enlarged view of constituent members
of a peripheral section of a stabilizer in FIG. 2.
[0033] FIG. 7 is a plan view of the mechanism illustrated in FIG.
1.
REFERENCE NUMERALS
[0034] 1: mainmast
[0035] 2: swash plate
[0036] 21: fixed swash
[0037] 22: rotation swash
[0038] 3: rotor head
[0039] 4: main rotor
[0040] 41: yoke
[0041] 42: blade holder
[0042] 43: main rotor blade
[0043] 5: stabilizer
[0044] 51: stabilizer bar
[0045] 52: stabilizer blade
[0046] 6: washout block
[0047] 7: center hub
[0048] 71: upper center hub
[0049] 72: lower center hub
[0050] 9: elevator lever
[0051] 10: wash arm control
[0052] 12: seesaw
[0053] 13: stabilize control rod
[0054] 14: mixing arm
[0055] 15: mixing arm rod
[0056] ES: elevator servo
[0057] AS: aileron servo
BEST MODE FOR CARRYING OUT THE INVENTION
[0058] The preferred embodiment of the present invention will be
described with reference to the accompanying drawings.
[0059] FIG. 1 is a perspective view of a mechanism for constituting
a rotor head and a swash linkage of an R/C helicopter according to
the present invention. FIG. 2 is a development perspective view of
constituent members of the mechanism of FIG. 1. FIG. 3 is a
development enlarged view of constituent members of a peripheral
section of a swash plate. FIG. 4 is a development enlarged view of
constituent members of a peripheral section of a main rotor. FIG. 5
is an enlarged cross-sectional view of essential parts of a
connecting portion of a main rotor and a mainmast. FIG. 6 is a
development enlarged view of constituent members of a peripheral
section of a stabilizer. FIG. 7 is a plan view of the mechanism
illustrated in FIG. 1.
[0060] In the individual drawings, reference numeral 1 denotes a
mainmast, reference numeral 2 denotes a swash plate, reference
numeral 3 denotes a rotor head including a main rotor 4 and a
stabilizer 5, an ES denotes an elevator servo, and an AS denotes an
aileron servo.
[0061] The embodiment that is illustrated in the drawings is
configured such that a pitch angle of a main rotor blade is
controlled by a Bell-Hiller control method. The present invention
is applied to an R/C helicopter having the configuration where an
airframe is light-weighted and small-sized to be used indoors.
[0062] In the description below, although not described, as other
members constituting the R/C helicopter, such as a main frame or a
tail rotor of the R/C helicopter, motors driving backward and
forward rotors, and a receiving device of a steering signal,
members that are already known in the related art can be used.
[0063] The mainmast 1 protrudes its upper portion to the upper side
of an airframe which is not illustrated, couples its lower portion
to a driving shaft of a motor provided in the airframe through a
gear, and is mounted to rotate by driving of the motor. In an outer
circumferential portion of the upper portion of the mainmast 1, a
cylindrical washout block 6 is mounted. In an upper end of the
mainmast 1, a center hub 7 that supports the rotor head 3 is
mounted and fixed to rotate integrally with the mainmast 1.
[0064] As illustrated in FIG. 2, the center hub 7 has a structure
where the center hub is divided into an upper center hub 71 fixed
to the upper end of the mainmast 1 and a lower center hub 72 fixed
to an outer circumferential surface of the mainmast 1 at the side
lower than the upper center hub 71. A seesaw 12 to be described in
detail below and the stabilizer 5 are mounted to the upper center
hub 71, and the main rotor 4 is mounted to the lower center hub
72.
[0065] The upper and the lower center hubs 71 and 72 are
appropriately fixed around the shaft of the mainmast 1 with a
predetermined angle, that is, a predetermined position from the
mainmast 1. As a result, an intersection angle of the main rotor 4
and the stabilizer 5 around the shaft of the mainmast 1, that is, a
phase difference of the rotations of both members can be set to an
appropriate angle. As will be described below, in this embodiment,
the phase difference is set to about 45 degrees.
[0066] As illustrated in FIG. 3, the swash plate 2 is configured to
rotably support a rotation swash 22 where pivots 22a and 22b
protrude in four circumferential directions through a bearing (not
illustrated), at the upper side of a fixed swash 21 where pivots
21a and 21b protrude in three circumferential directions.
[0067] The swash plate 2 causes the mainmast 1 to pass through an
opening formed in the center thereof and is mounted inclineably
around the shaft in a direction orthogonal to the mast as the
center.
[0068] That is, on the lower side of the swash plate 2, an elevator
lever 9 having a horizontally long frame shape that is connected to
a servo horn of the elevator servo ES through a rod 8a is disposed,
and both ends 9a and 9a of the elevator lever 9 that can be
inclined are connected to the pivots 21a and 21a of outer
circumference facing positions of the fixed swash 21. In the
elevator lever 9, its center portions 9b and 9b are connected in a
main frame which is not illustrated to freely rotate. A servo horn
of the aileron servo AS is connected to the pivots 21b that are
disposed at the positions 90 degrees shifted from both pivots 21a
of the fixed swash 21 at the facing positions, through a rod 8b. On
both sides of the washout block 6 that is fixed to just above the
mainmast 1 on the swash plate 2, wash control arms 10 and 10 are
disposed. Center portions 10a and 10a of the wash control arms 10
are connected in an outer circumferential portion 61 of the washout
block 6 to freely rotate, and rotatable ends 10b and 10b of the
wash control arms 10 are connected to the pivots 22a and 22a of the
rotation swash 22 at the facing positions to freely rotate.
[0069] When the elevator servo ES is driven and the rod 8a that is
connected to the servo horn is elevated, with center portions 9b
and 9b of the elevator lever 9 as the center, one of both ends of
the elevator lever 9 ascends and the other descends. As a result,
the fixed swash 21 and the rotation swash 22 are inclined around
the mainmast 1 parallel to the elevator lever 9.
[0070] If the aileron servo AS is driven and the rod 8b that is
connected to the servo horn is elevated, with a line segment
connecting the pivots 21a and 21a of the fixed swash 21 as an axis,
an end of the pivot 21b that the rod 8b of the fixed swash 21 is
connected and an end that faces the end of the pivot 21b ascend or
descend, and the fixed swash 21 and the rotation swash 22 are
inclined around the mainmast 1.
[0071] The rotor head 3 that comprises the main rotor 4 and the
stabilizer 5 is mounted above the swash plate 2 to rotate
integrally with the mainmast 1 by the center hub 7 fixed to the
mainmast 1, is connected to the swash plate 2 through a linkage,
such as the wash control arm 10 or a mixing arm rod 15 to be
described in detail below, and is mounted such that pitch angles of
the main rotor 4 and the stabilizer 5 change by the inclining
operation of the swash plate 2.
[0072] The main rotor 4 is formed to have the light weight as a
whole using main rotor blades 43 made of expanded polystyrene. As
illustrated in FIGS. 2 and 4, the main rotor 4 comprises a yoke 41
that is formed by protruding the pivots 41a and 41a backward and
forward, a pair of upper and lower blade holders 42 and 42 that are
fixed to both sides of the yoke 41, and main rotor blades 43 and 43
that are mounted integrally to both sides of the yoke 41 at
predetermined pitch angles, by causing an insertion bolt to
penetrate a base end from both a top surface and a bottom surface
by the blade holders 42 and 42.
[0073] The main rotor 4 mounts the yoke 41 to an outer
circumferential portion of an upper portion of the lower center hub
72 fixed to the mainmast 1, inclines the yoke 41 in an axial
direction orthogonal to the mainmast 1 while rotating integrally
with the mainmast 1, appropriately inclines the entire main rotor
4, and changes the pitch angles of the main rotor blades 43 and
43.
[0074] Specifically, as illustrated in FIG. 5, in a state where the
yoke 41 is mounted to the outer circumferential portion of the
lower center hub 72, the yoke 41 protrudes pins 11 and 11 from a
facing inner circumferential surface thereof and is connected on an
outer circumferential surface of the lower center hub 72 to freely
rotate. In the pivots 41a and 41a of the yoke 41, one end of pitch
rods 16 and 16 to be described in detail below is connected to
freely rotate. As illustrated in FIG. 5B, if the pivots 41a and 41a
are displaced upward and downward by the pitch rods 16 and 16, the
entire main rotor 4 is inclined in an arrow direction Ra around the
lower center hub 72 with the pin 11 and 11 as a fulcrum, and the
pitch angles of the main rotor blades 43 and 43 with respect to the
mainmast 1 change.
[0075] As illustrated in FIGS. 2 and 6, the stabilizer 5 is
configured by mounting stabilizer blades 52 and 52 integrally to
both sides of a stabilizer bar 51 having its center portion as a
frame-shaped opening 51a.
[0076] The stabilizer 5 supports the opening 51a to the upper
center hub 71 fixed to the upper end of the mainmast 1 through the
seesaw 12, and is mounted to rotate integrally with the mainmast 1,
with a phase difference of about 45 degrees with the main rotor
4.
[0077] Specifically, the upper center hub 71 that has an upper
portion curved in a U shape is fixed to the upper end of the
mainmast 1, and pivots a center portion 12a of the seesaw 12 to
shaft portions 71a and 71a provided in the U-shape curved portion
of the upper center hub 71 to freely rotate. The upper center hub
71 is fixed at an angle shifted from an angle of the lower center
hub 72 around the shaft of the mainmast 1. If an axis line
connecting the shaft portions 71a and 71a is projected onto an axis
line connecting both pins 11 and 11 that pivot the main rotor 4 to
the lower center hub 72 to freely rotate, both axis lines cross
each other at an angle of about 45 degrees, and the main rotor 4
and the stabilizer 5 that are mounted to the upper and lower center
hubs 71 and 72 rotate with a phase difference of about 45
degrees.
[0078] The stabilizer 5 tacks bearings 51b and 51b provided in the
opening 51a of the stabilizer bar 51 on the both ends 12b and 12b
of the seesaw 12 supported to the upper center hub 71 to freely
rotate, by means of pins which is not illustrated. As illustrated
in FIG. 6, the entire stabilizer 5 seesaws together with the seesaw
12 along an arrow direction Sa with the shaft portions 71a and 71a
of the upper center hub 71 as a fulcrum, and the stabilizer blades
52 and 52 are inclined along an arrow direction Sb with a line
connecting the bearings 51b and 51b as an axis.
[0079] In center portions of inner surfaces of both sides of the
opening 51a of the stabilizer 51, one end of the stabilizer control
rods 13 and 13 is respectively connected to freely rotate, and the
other ends thereof are connected to the pivots 10c and 10c provided
in the other ends of the wash control arms 10 and 10 to freely
rotate.
[0080] On both sides of the seesaw 12, bearings 12c and 12c are
provided at symmetrical positions that are apart from the center
portions 12a at an equivalent interval, and mixing arms 14 and 14
are rotatably pivoted to the bearings 12c and 12c by means of
pins.
[0081] In the mixing arms 14 and 14, the lengths from the shaft
portions pivoted to the bearings 12c to both ends are different. In
pivots 14a that are provided in long-side ends, one of the mixing
arm rods 15 is rotatably connected. In pivots 14b that are provided
in short-side ends, one end of the pitch rods 16 is rotatably
connected. The other ends of the mixing arm rods 15 and 15 are
rotatably connected to the pivots 22b and 22b of the rotation swash
22, and the other ends of the pitch rods 16 and 16 are rotatably
connected to the pivots 41a and 41a of the yoke 41 of the main
rotor 4. By these arms and rods, the swash linkage is
configured.
[0082] According to the rotor head 3 of the R/C helicopter of this
embodiment that is configured in the above-described way, if the
elevator servo ES or the aileron servo AS is driven and both servo
horns are operated, the ends of the rods 8a and 8b that are
connected to the individual servo horns are displaced upward and
downward, and the swash plate 2 is appropriately inclined around
the mainmast 1. As a result, the mixing arm rods 15 and 15 that are
connected to the pivots of the circumferential sides of the
rotation swash 22 the wash control arms 10 and 10 are displaced to
change the pitch angles of the main rotor blades 43 and 43 and the
stabilizer blades 52 and 52.
[0083] That is, the displacements of the mixing arm rods 15 and 15
according to the inclination of the swash plate 2 are transmitted
to the main rotor 4 through the mixing arms 14 and 14 and the pitch
rods 16 and 16, and the main rotor blades 43 and 43 are inclined in
an arrow direction Ra of FIG. 5 to change the pitch angles. The
displacements of the wash control arms 10 and 10 cause the
stabilizer control rods 13 and 13 to operate, thereby inclining the
entire stabilizer 5 in an arrow direction Sb of FIG. 6 and changing
the pitch angles of the stabilizer blades 52 and 52.
[0084] If the stabilizer blades 52 and 52 receive a wind pressure,
the entire stabilizer 5 seesaws together with the seesaw 12 in an
arrow direction Sa of FIG. 6 with the shaft portions 71a and 71a of
the upper center hub 71 as a fulcrum. By the seesaw operation, the
mixing arms 14 and 14 rotate around the seesaw 12 and the
displacements thereof are transmitted to the main rotor 4 through
the pitch rods 16 and 16, thereby inclining the main rotor 4 and
changing the pitch angles of the main rotor blades 43 and 43.
[0085] If the main rotor 4 is inclined and the pitch angles of the
main rotor blades 43 and 43 are changed, a gyro pre-session acts on
the main rotor 4. However, since the main rotor blades 43 and 43
are formed of a light-weighted material and the main rotor 4 is
configured to have the light weight, the gyro pre-session appears
after being delayed by about 45 degrees with respect to a rotation
direction of the main rotor 4.
[0086] In this embodiment as illustrated in FIG. 7, when an axis
line BL connecting between fore-end of the main rotor blades 43 and
43 running through the shaft of the mainmast 1 and an axis line SL
connecting between fore-end of the stabilizer blades 52 and 52
running through the shaft of the mainmast 1 are projected onto the
surface orthogonal to the mainmast 1, an intersection angle .alpha.
of both axis lines becomes about 45 degrees, and the main rotor
blades 43 and 43 and the stabilizer blades 52 and 52 are configured
to integrally rotate with a phase difference of about 45 degrees.
Accordingly, if the pitch angles of the main rotor blades 43 and 43
change and a direction of force of the gyro pre-session acting on
the airframe and a control direction of the airframe become matched
with each other, and the flying operation of the R/C helicopter can
be stabilized.
EXAMPLE
[0087] The rotor head 3 of this embodiment is mounted to an
airframe of an indoor helicopter to constitute an R/C helicopter.
The total weight of the airframe including electrical components,
such as a motor, a receiving device, and a battery is 150 g. The
main rotor blade 43 is made of expanded polystyrene, and its total
length (L) from the base end to the fore-end is 153 mm and its
weight is 2 g. The fixed positions of the upper and the lower
center hubs 71 and 72 are adjusted and a phase difference
(intersection angle .alpha.) of the main rotor 4 and the stabilizer
5 is set to about 45 degrees.
COMPARATIVE EXAMPLE
[0088] The airframe, the rotor head 3, and the main rotor blade 43
that are the same as those in the said embodiment are used, the
fixed positions of the upper and the lower center hubs 71 and 72
are adjusted, and a phase difference (intersection angle .alpha.)
of the main rotor 4 and the stabilizer 5 is set to about 90
degrees, thereby constituting an R/C helicopter.
[0089] When the R/C helicopter according to the comparative example
is made to fly by the remote control, if the operation stick of the
transmitter is operated, the flying posture is collapsed, the
airframe shakes, control of a flying direction of the airframe is
difficult to be smoothly performed, and the control operation is
difficult.
[0090] Meanwhile, in the R/C helicopter according to the
embodiment, if the operation stick of the transmitter is operated,
the airframe smoothly flies in an operation direction without
shaking, and the flying direction can be stably controlled without
collapsing the flying posture. As a result, it is confirmed that
operability is improved in the airframe according to the
embodiment, as compared with the airframe according to the
comparative example.
[0091] In the R/C helicopter according to the embodiment, it is
confirmed that the flying stability and the operability are
improved by appropriately setting the phase difference
(intersection angle .alpha.) of the main rotor 4 and the stabilizer
5. As a result, it is confirmed that the flying is stable, if the
phase difference is in a range of 30 to 60 degrees. Among them,
when the phase difference is in a range of 40 to 50 degrees, the
flying is most stable, the flying direction is controlled without
collapsing the flying posture, and the operability is most
superior.
[0092] The embodiment illustrated in the drawings is only
exemplary, and the present invention can be applied to an R/C
helicopter of another preferable embodiment. In the embodiment
illustrated in the drawings, the main rotor blades are disposed as
fixed pitches to constitute the main rotor. However, the main rotor
may be configured by mounting a pitch servo, such that the pitch
angles are controlled by collective pitch control. The swash
linkage that connects the rotor head and the swash plate can be
appropriately configured, and the configuration of the Bell type or
the Hiller type is enabled. The stabilizer bar may be disposed at
the lower side of the main rotor to constitute the rotor head. The
center hub is divided into the upper center hub and the lower
center hub. However, if the phase difference of the optimal
rotation of the main rotor and the stabilizer is clear according to
the weight or configuration of the airframe of the R/C helicopter,
the upper and the lower center hubs may be integrally
configured.
* * * * *